Moveable joint

ABSTRACT

A moveable joint suitable for connection with a tubular member including a socket member having an inner surface defining a cavity and a rotation member having an outer surface corresponding to the cavity wherein the rotation member is journaled for rotation in said cavity. The rotation member has an inner surface defining a cylindrical bore through the rotation member and centered on a longitudinal axis of rotation member, the cylindrical bore being configured to receive a tubular member. The moveable joint further includes a releasable locking mechanism for releasably locking a tubular member in the cylindrical bore so that when the tubular member is locked in the cylindrical bore the tubular member and the rotation member are fixed with respect to one another and are rotatable relative to the socket member. The locking mechanism includes a cage connected to the rotation member.

This invention relates to a moveable joint, and more specifically to amoveable joint that is capable of releasably locking to a tubular membersuch as a wellbore casing member, a drill string tubing member, a pipemember, a collared tubing member, or a steel catenary riser (SCR).

BACKGROUND

For the reasons or rotatability and universality amongst others, thedrilling of subterranean wells involves the use of many tubular shapedmembers. For example, each of a wellbore casing member, a drill stringtubing member, a pipe member, a collared tubing member, and a steelcatenary riser (SCR) are generally tubular in form. Such tubular membersoften rise from a subsea level and require mounting or otherwise fixingto a structure such as a rig. However, given that the motion of the seacauses movement of the tubular member, there is the risk of fatigue ordamage to the tubular member and/or the structure that it is attacheddue to the movement of the tubular member. Joints including dampers(e.g. rubber dampers) reduce this problem to an extent but theelastomeric nature of dampers results in a biasing force that may beundesirable or that exerts a potentially damaging additional force onthe tubular member.

It is an object of the present invention to provide an improved jointthat mitigates at least some of the problems associated with the priorart.

BRIEF SUMMARY OF THE DISCLOSURE

The present invention is defined in the appended claims.

In accordance an aspect of the present invention there is provided amoveable joint suitable for connection with a tubular member,comprising:

-   -   a socket member having an inner surface defining a cavity; and    -   a rotation member having an outer surface corresponding to said        cavity, said rotation member being journaled for rotation in        said cavity;

wherein said rotation member has an inner surface defining a cylindricalbore through said rotation member and centred on a longitudinal axis ofsaid rotation member, the cylindrical bore being configured to receive atubular member, where said moveable joint further comprises a releasablelocking mechanism for releasably locking a tubular member in saidcylindrical bore so that when said tubular member is locked in saidcylindrical bore said tubular member and said rotation member are fixedwith respect to one another and are rotatable relative to said socketmember.

Preferably, said cavity corresponds to a spherical segment and saidrotation member is a ball member that has an outer surface correspondingto a spherical segment that is complementary to said cavity. Said ballmember preferably has three rotational degrees of freedom with respectto said socket member.

The moveable joint preferably further comprises one or more limitingmembers that are arranged to limit rotational movement of the rotationmember relative to the socket member.

The locking mechanism comprises a cage connected to the rotation memberand having a plurality of windows partially closing recesses in theinner surface of said rotation member, which recesses are elongate in alongitudinal direction parallel the longitudinal axis, house a rollerand have a base inclined in said longitudinal direction so that at alower end of each recess the roller protrudes through said window and atan upper end thereof the roller protrudes less or not at all. Saidrotation member preferably comprises an outer sleeve having afrusto-conical bore centered on said longitudinal axis, a clamp memberin the sleeve formed by clamp-segments, each having side faces, endfaces, a frusto-conical exterior surface adapted to match saidfrusto-conical bore, and a cylindrical interior surface defining saidcylindrical bore, wherein said cage comprises a cage-segment in respectof each clamp-segment. Further preferably, each of said clamp segmentshas a lift eye by which said clamp elements may be lifted with respectto said sleeves so that said clamp-segments slide up said frusto-conicalbore separating from one another in a peripheral direction as theyprogress.

A key on one of said frusto-conical surfaces is preferably engageable ina groove in the other of said frusto-conical surfaces such that torqueapplied to said clamp-segments is transmitted to said sleeve. Said keyis preferably slidable in said slot and said key and said slot areparallel the cone angle of said frusto-conical surfaces.

In one preferable arrangement, there are three clamp-segments.

In a further or alternative preferable arrangement, a bias mechanismurges said clamp-segments apart from each other in a peripheraldirection, where said bias mechanism is preferably a spring disposedbetween said side faced of the clamp segments.

Between a clamp position and an open position of the moveable joint, theclamp-segments preferably move from a position in which the arcs of thecage-segments lie in a common cylindrical surface and the frusto-conicalsurfaces are flush with each other, to a release position in which saidside faces are spaced from one another and said frusto-conical surfaceshave only line contact between them.

In one preferable embodiment, said frusto-conical surfaces arepart-cylindrical surfaces that are inclined toward said longitudinalaxis.

Said rollers are preferably balls and said recesses preferably have asemi-circular base of diameter substantially equal to the diameter ofthe balls.

In one preferable arrangement, one or both of the outer surface of therotation member and the inner surface of the socket member comprise alow friction surface so as to permit rotation of the rotation memberrelative to the socket member. In a further or alternative arrangement,the moveable joint further comprises bearings between the rotationmember and the socket member so as to permit rotation of the rotationmember relative to the socket member.

In one preferable embodiment, said cylindrical bore passes through therotation member such that the cylindrical bore has two open ends, thesocket member being configured around said rotation member such that atubular member may protrude from both of the open ends of thecylindrical bore. Said socket member preferably comprises two socketsegments that are connectable to one another around said rotationmember.

Alternatively, said cylindrical bore is a blind bore such that thecylindrical bore has only one open end, the socket member beingconfigured around said rotation member such that a tubular member mayprotrude from the open end of the cylindrical bore.

The moveable joint preferably includes a tubular member, wherepreferably said tubular member is one of a wellbore casing member, adrill string tubing member, a pipe member, a collared tubing member, anda steel catenary riser (SCR).

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention are further described hereinafter withreference to the accompanying drawings, in which:

FIG. 1 is a cut-away view of a moveable joint in accordance with anembodiment of the present invention;

FIG. 2 is a cross-sectional view of a moveable joint in accordance withan embodiment of the present invention; and

FIG. 3 is a detailed cross-sectional view of part of the moveable jointof FIG. 3.

DETAILED DESCRIPTION

FIG. 1 shows a cut-away view of a moveable joint 10 in accordance withan embodiment of the present invention. The joint 10 includes a socketmember 12 and a rotation member 14 rotatable in the socket member 12.The socket member 12 has an inner surface 13 defining a cavity and therotation member 14 has an outer surface 16 a corresponding to the cavityformed by the inner surface 13 of the socket member 12. In theembodiment of FIG. 1, the socket member 12 is formed of two socketsegments 12 a, 12 b that connect to one another around the rotationmember 14.

The rotation member 14 has an inner surface 22 defining a substantiallycylindrical bore in the rotation member 14 that is configured to receivea tubular member 100. The tubular member may be one of, but is notnecessarily limited to being, a wellbore casing member, a drill stringtubing member, a pipe member, a collared tubing member, and a steelcatenary riser (SCR). Indeed, the present invention is suited for usewith any suitable substantially tubular member.

The joint 10 further includes a releasable locking mechanism (which willbe described in more detail below) for releasably locking the tubularmember 100 in the cylindrical bore of the rotation member 14. When thetubular member 100 is locked to the rotation member 14 by the lockingmechanism, the tubular member 100 and the rotation member 14 aresubstantially fixed with respect to one another and are moveable as aconnected unit such that the rotation member 14 and tubular member 100are rotatable in the cavity of the socket member 12.

In the specific embodiment shown in FIG. 1, the rotation member 14 is aball member that has an outer surface corresponding to a sphericalsegment that is complementary to cavity of the socket member 12. Indeed,the cavity of the socket member 12 also corresponds to a sphericalsegment in the embodiment of FIG. 1. The ball member 14 has threerotational degrees of freedom with respect to the socket member 12.Indeed, the ball member 14 (and tubular member 100 when locked therein)is rotatable about each of x, y and z axes indicated in FIG. 1. Thejoint 10 may include limiting members that are positioned and configuredto limit rotational movement of the ball member 14 relative to thesocket member 12. For example, the limiting members may be placed so asto prevent the tubular member 100 contacting the socket member 12through rotation of the ball member 14.

The ball member 14 of FIG. 1 comprises an outer sleeve 16 whose outersurface is the outer surface 16 a of the ball member 14. The outersleeve 16 has an inner surface 16 b defining a frusto-conical bore whichis centered on a longitudinal axis 200 of the ball member 14 (see FIG.2). Disposed within the frusto-conical bore is a clamp member 18 formedof three clamp-segments 18 a, 18 b, 18 c. Each of the clamp segments 18a, 18 b, 18 c has side faces 19 d, end faces 19 b, 19 c and afrusto-conical exterior surface 19 a adapted to match the frusto-conicalbore of the outer sleeve 16. In preferable embodiments (not shown in theFigures), there is a key on one or more of the frusto-conical surfaces19 a, 16 b that is engageable in a groove in the other of thefrusto-conical surfaces 19 a, 16 b so that torque applied to the clampsegments 18 a, 18 b, 18 c (e.g. by movement of the tubular member 100fixed therein) is transmitted to the sleeve 16 so that the ball member14 as a whole rotates relative to the socket member 12. In particularlypreferable embodiments, the key is slidable in the slot and both of thekey and the slot are orientated parallel to the cone angle of thefrusto-conical surfaces 19 a, 16 b.

The clamp segments 18 a, 18 b, 18 c are removable from the sleeve 16such that they may be assembled in the sleeve 16 around the tubularmember 100. This arrangement allows a tubular member 100 with flanged orotherwise radially protruding parts to pass through the ball member 14prior to the clamp member 18 (i.e. the clamp segments 18 a, 18 b, 18 cforming the clamp member 18) being assembled in the frusto-conical boreof the sleeve 16 around the tubular member 100.

When assembled, the clamp segments 18 a, 18 b, 18 b are disposed withtheir side faces 19 abutting the side faces 19 of the adjacent clampsegments 18 a, 18 b, 18 c. The clamp segments 18 a, 18 b, 18 c mayinclude a bias mechanism that urges the clamp segments apart from eachother in a peripheral direction so that when the clamp segments are moveupward out of the frusto-conical bore, they are urged apart. The biasmechanism is preferably a spring disposed between the side faces 19 ofthe clamp segments 18 a, 18 b, 18 c.

Inner surfaces of the clamp segments 18 a, 18 b, 18 c include aplurality of recesses 24 that each house (partially, at least) a roller26. Additionally, a cage 28 circumvents the cylindrical bore where aninner surface of the cage 28 is the inner surface 22 of the ball member14 which defines the cylindrical bore. The cage 28 is formed of cagesegments (not shown individually) where each cage segment is associatedwith one of the clamp segments 18 a, 18 b, 18 c. The cage 28 has aplurality of windows 18 a that partially close the recesses 24. Each ofthe recesses is elongate in a longitudinal direction parallel to thelongitudinal axis and has a base inclined in the longitudinal directionso that at a lower end 24 a of each recess 24 the roller 26 protrudesthrough the window 28 a (as shown in FIGS. 2 and 3), and at an upper end24 b of the recess 24 the roller 26 protrudes less or not at all (notshown). The cage segments are connected to the clamp segments 18 a, 18b, 18 c by a collar 20, which is also formed in segments 20 a, 20 b, 20c

As described above, the clamp segments 18 a, 18 b, 18 c are moveablebetween a clamp position and an open position (i.e. assembled andnon-assembled) where in the clamp position the arcs of the cage segmentslie in a common cylindrical surface and the frusto-conical surfaces 19a, 16 b are flush with each other, and in the open position the sidefaces 19 are spaced from one another and said frusto-conical surfaces 19a, 16 b have only line contact between them. The clamp segments 18 a, 18b, 18 c may each have a lift eye by which they may be lifted withrespect to the sleeve 16 so that the clamp segments 18 a, 18 b, 18 cslide up the frusto-conical bore, separating from one another in aperipheral direction as they progress.

In one embodiment, the frusto-conical surfaces 19 a, 16 b arepart-cylindrical surfaces that are inclined toward the longitudinal axis200.

In use, a tubular member 100 is positioned in the cylindrical bore andmoved downwards (as indicated by direction A in FIG. 3) relative to theball member 14. The rollers 26 are caused to move downwards towards thelower ends 24 a of the recesses so that they progressively protrudefurther (i.e. radially inwardly) through the windows 28 a and bite intothe tubular member 100 to “lock” the tubular member 100 relative to theball member 14. In order to release the tubular member 100 from the ballmember 14, the tubular member 100 must be moved upwards (as indicated bydirection B in FIG. 3) relative to the ball member 14 so that therollers 26 are caused to move towards the upper ends 24 b of therecesses 24 where they protrude less and permit further movement of thetubular member 100 relative to the ball member 14. Thus, the arrangementof rollers 26 in recesses 24 provides a releasable locking mechanismthat releasably connects the tubular member 100 to the ball member 14.As discussed above, when the tubular member 100 is locked with respectto the ball member 14, the tubular member 100 and ball member 14 aretogether rotatable as a unit relative to the socket 12.

Each of the rollers 26 may be or comprise a substantially sphericalmember, such as a steel ball bearing. However, other materials andshapes are also within the scope of the present disclosure. For example,each of the rollers 26 may alternatively be a cylindrical or tapered pinconfigured to roll up and down the ramps defined by the recesses 24.

Additionally or alternatively, the cage 28 (or its individual cagesegments) can be biased in a direction parallel the longitudinal axis200 so as to bias the rollers 26. This arrangement can permit smallerwindows 28 a in the cage 28 that permit the rollers 26 to protrudetherefrom but not fall out. The biased cage 28 can be moved axially(i.e. up or down parallel the longitudinal axis 200) to bias the rollers26 to the upper end 24 b or lower end 24 a of the recesses 24, movingbetween an engaging and disengaging position, respectively. The biasedcage 28 may be mechanically sprung or hydraulically driven.

Although the above-described embodiment is a particularly preferablearrangement of the moveable joint 10 of the present invention, thepresent invention is not limited to that specific arrangement. Indeed,the rotation member 14 may have a shape that is not a spherical segment(e.g. to form a condyloid joint) where the cavity formed by the socketmember 12 corresponds to the shape of the rotation member 14.

The outer surface 16 a of the rotation member 14 and/or the innersurface 13 of the socket member 12 may be configured to be low frictionsuch that movement of the rotation member 14 relative to the socketmember 12 is permitted. Indeed, the friction of the surfaces 16 a, 13may be configured so that a desired amount or rate of relative movementof the rotation member 14 relative to the socket member 12 is permitted.Additionally or alternatively, bearing members and/or lubricants may bedisposed between the rotation member 14 and the socket member 12 so asto permit relative movement therebetween.

The cylindrical bore of the rotation member 16 may pass entirely throughthe rotation member 16 such that the cylindrical bore has two open ends(as shown in the Figures). Alternatively, the cylindrical bore may be ablind bore having just a single open end such that the cylindrical boredoes not pass entirely through the rotation member 16. In either case,the socket member 12 should be configured around the rotation member 14so that rotation of the rotation member 14 is permitted and the tubularmember 100 is accommodated by the socket member 12.

The rotation member 14 has been described as being composed of varioussegmented components. The skilled person will appreciate that theprecise number of segments described is not limiting and that theinvention may comprise any suitable number of segments. In alternativeembodiments, for example, the rotation member 14 may be formed of wholenon-segmented components as opposed to the described segmentedcomponents. Indeed, the rotation member 14 may consist of a singlecomponent and a locking mechanism for locking the tubular member 100 tothe rotation member 14.

In use the socket member 12 may be fixed to a rig or other structure sothat the tubular member 100 locked to the rotation member 14 may moverelative to the socket member 12 and the structure that it is attachedto but remain axially fixed (i.e. along a direction parallel to thelongitudinal axis 200) relative to the socket member 12 and thestructure that it is attached to. Amongst other advantages, the presentinvention provides an arrangement where the tubular member 100 and/orthe structure to which the socket member 12 is attached to experiencelower fatigue and stresses whilst maintaining a connection therebetween.

Throughout the description and claims of this specification, the words“comprise” and “contain” and variations of them mean “including but notlimited to”, and they are not intended to (and do not) exclude othermoieties, additives, components, integers or steps. Throughout thedescription and claims of this specification, the singular encompassesthe plural unless the context otherwise requires. In particular, wherethe indefinite article is used, the specification is to be understood ascontemplating plurality as well as singularity, unless the contextrequires otherwise.

Features, integers, characteristics, compounds, chemical moieties orgroups described in conjunction with a particular aspect, embodiment orexample of the invention are to be understood to be applicable to anyother aspect, embodiment or example described herein unless incompatibletherewith. All of the features disclosed in this specification(including any accompanying claims, abstract and drawings), and/or allof the steps of any method or process so disclosed, may be combined inany combination, except combinations where at least some of suchfeatures and/or steps are mutually exclusive. The invention is notrestricted to the details of any foregoing embodiments. The inventionextends to any novel one, or any novel combination, of the featuresdisclosed in this specification (including any accompanying claims,abstract and drawings), or to any novel one, or any novel combination,of the steps of any method or process so disclosed.

The reader's attention is directed to all papers and documents which arefiled concurrently with or previous to this specification in connectionwith this application and which are open to public inspection with thisspecification, and the contents of all such papers and documents areincorporated herein by reference.

1. A moveable joint suitable for connection with a tubular member,comprising: a socket member having an inner surface defining a cavity;and a rotation member having an outer surface corresponding to saidcavity, said rotation member being journaled for rotation in saidcavity; wherein said rotation member has an inner surface defining acylindrical bore through said rotation member and centered on alongitudinal axis of said rotation member, the cylindrical bore beingconfigured to receive a tubular member, where said moveable jointfurther comprises a releasable locking mechanism for releasably lockinga tubular member in said cylindrical bore so that when said tubularmember is locked in said cylindrical bore said tubular member and saidrotation member are fixed with respect to one another and are rotatablerelative to said socket member; and wherein said locking mechanismcomprises a cage connected to the rotation member and having a pluralityof windows partially closing recesses in the inner surface of saidrotation member, which recesses are elongate in a longitudinal directionparallel the longitudinal axis, house a roller and have a base inclinedin said longitudinal direction so that at a lower end of each recess theroller protrudes through said window and at an upper end thereof theroller protrudes less or not at all.
 2. The moveable joint according toclaim 1, wherein said cavity corresponds to a spherical segment and saidrotation member is a ball member that has an outer surface correspondingto a spherical segment that is complementary to said cavity.
 3. Themoveable joint according to claim 2, wherein said ball member has threerotational degrees of freedom with respect to said socket member.
 4. Themoveable joint according to any preceding claim 1, further comprisingone or more limiting members that are arranged to limit rotationalmovement of the rotation member relative to the socket member.
 5. Themoveable joint according to claim 1, wherein said rotation membercomprises an outer sleeve having a frusto-conical bore centered on saidlongitudinal axis, a clamp member in the sleeve formed byclamp-segments, each having side faces, end faces, a frusto-conicalexterior surface adapted to match said frusto-conical bore, and acylindrical interior surface defining said cylindrical bore, whereinsaid cage comprises a cage-segment in respect of each clamp-segment. 6.The moveable joint according to claim 5, wherein each of said clampsegments has a lift eye by which said clamp elements may be lifted withrespect to said sleeves so that said clamp-segments slide up saidfrusto-conical bore separating from one another in a peripheraldirection as they progress.
 7. The moveable joint according to claim 5,wherein a key on one of said frusto-conical surfaces is engageable in agroove in the other of said frusto-conical surfaces such that torqueapplied to said clamp-segments is transmitted to said sleeve.
 8. Themoveable joint according to claim 7, wherein said key is slidable insaid slot and said key and said slot are parallel the cone angle of saidfrusto-conical surfaces.
 9. The moveable joint according to claim 5,wherein there are three clamp-segments.
 10. The moveable joint accordingto claim 5, wherein a bias mechanism urges said clamp-segments apartfrom each other in a peripheral direction, where said bias mechanism ispreferably a spring disposed between said side faced of the clampsegments.
 11. The moveable joint according to claim 5, wherein between aclamp position and an open position of the moveable joint, theclamp-segments move from a position in which the arcs of thecage-segments lie in a common cylindrical surface and the frusto-conicalsurfaces are flush with each other, to a release position in which saidside faces are spaced from one another and said frusto-conical surfaceshave only line contact between them.
 12. The moveable joint according toclaim 5, wherein said frusto-conical surfaces are part-cylindricalsurfaces that are inclined toward said longitudinal axis.
 13. Themoveable joint according to claim 1, wherein said rollers are balls andsaid recesses have a semi-circular base of diameter substantially equalto the diameter of the balls.
 14. The moveable joint according to claim1, wherein one or both of the outer surface of the rotation member andthe inner surface of the socket member comprise a low friction surfaceso as to permit rotation of the rotation member relative to the socketmember.
 15. The moveable joint according to 1, further comprisingbearings between the rotation member and the socket member so as topermit rotation of the rotation member relative to the socket member.16. The moveable joint according to claim 1, wherein said cylindricalbore passes through the rotation member such that the cylindrical borehas two open ends, the socket member being configured around saidrotation member such that a tubular member may protrude from both of theopen ends of the cylindrical bore.
 17. The moveable joint according toclaim 16, wherein said socket member comprises two socket segments thatare connectable to one another around said rotation member.
 18. Themoveable joint according to claim 1, wherein said cylindrical bore is ablind bore such that the cylindrical bore has only one open end, thesocket member being configured around said rotation member such that atubular member may protrude from the open end of the cylindrical bore.19. The moveable joint according to claim 1, including a tubular member.20. The moveable joint according to claim 19, wherein said tubularmember is one of a wellbore casing member, a drill string tubing member,a pipe member, a collared tubing member, and a steel catenary riser(SCR).
 21. (canceled)